High-order Laue zone (HOLZ) line patterns of an Al70Co15Ni15quasicrystalline decagonal phase with a periodicity of 0·4 nm along the tenfold axis have been obtained experimentally with a large angular range by connecting a series of large-angle convergent-beam electron diffraction patterns. The computer-simulated HOLZ line patterns, which were calculated using the cut-and-projection method and a simple quasi-lattice model, show good agreement with the experimental observations.